/*
 * gleem -- OpenGL Extremely Easy-To-Use Manipulators.
 * Copyright (C) 1998, 1999, 2002 Kenneth B. Russell (kbrussel@alum.mit.edu)
 * See the file LICENSE.txt in the doc/ directory for licensing terms.
 */

package gnu.gleem;

import java.util.*;

import javax.media.opengl.GL;

import gnu.gleem.linalg.*;

/** Triangle-based manipulator part. This is the base class for most
    of the ManipParts that GLEEM uses internally. You can feel free to
    subclass this if you want to replace geometry in the manipulators,
    or re-derive from ManipPart. See ManipPartLineSeg for an example. */

public class ManipPartTriBased extends ManipPart {
  private Vec3f   color;
  private Vec3f   highlightColor;
  private boolean highlighted;
  private boolean pickable;
  private boolean visible;
  /** Direct references down to subclass-specific data */
  private Vec3f[] vertices;
  private Vec3f[] normals;
  private int[]   vertexIndices;
  private int[]   normalIndices;
  /** Current transformation matrix */
  private Mat4f   xform;
  /** Transformed vertices and normals */
  private Vec3f[] curVertices;
  private Vec3f[] curNormals;

  public ManipPartTriBased() {
    color          = new Vec3f(0.8f, 0.8f, 0.8f);
    highlightColor = new Vec3f(0.8f, 0.8f, 0.2f);
    highlighted    = false;
    pickable       = true;
    visible	   = true;
    vertices	   = null;
    normals        = null;
    vertexIndices  = null;
    normalIndices  = null;
    xform          = new Mat4f();
    xform.makeIdent();
    curVertices    = null;
  }

  /** Default color is (0.8, 0.8, 0.8) */
  public void setColor(Vec3f color) {
    this.color.set(color);
  }

  public Vec3f getColor() {
    return new Vec3f(color);
  }

  /** Default highlight color is (0.8, 0.8, 0) */
  public void setHighlightColor(Vec3f highlightColor) {
    this.highlightColor.set(highlightColor);
  }

  public Vec3f getHighlightColor() {
    return new Vec3f(highlightColor);
  }

  public void intersectRay(Vec3f rayStart,
			   Vec3f rayDirection,
			   List  results,
			   Manip caller) {
    consistencyCheck();
    if (!pickable) {
      return;
    }

    IntersectionPoint intPt = new IntersectionPoint();
    HitPoint hitPt = new HitPoint();
    hitPt.manipulator = caller;
    hitPt.manipPart = this;
    for (int i = 0; i < vertexIndices.length; i+=3) {
      int i0 = vertexIndices[i];
      int i1 = vertexIndices[i+1];
      int i2 = vertexIndices[i+2];
      if (RayTriangleIntersection.intersectRayWithTriangle(rayStart,
							   rayDirection,
							   curVertices[i0],
							   curVertices[i1],
							   curVertices[i2],
							   intPt)
	  == RayTriangleIntersection.INTERSECTION) {
	// Check for intersections behind the ray
	if (intPt.getT() >= 0) {
	  hitPt.rayStart = rayStart;
	  hitPt.rayDirection = rayDirection;
	  hitPt.intPt = intPt;
	  results.add(hitPt);
	}
      }
    }
  }

  public void setTransform(Mat4f xform) {
    this.xform.set(xform);
    recalcVertices();
  }

  public void highlight() {
    highlighted = true;
  }

  public void clearHighlight() {
    highlighted = false;
  }

  /** Default is pickable */
  public void setPickable(boolean pickable) {
    this.pickable = pickable;
  }

  public boolean getPickable() {
    return pickable;
  }

  /** Default is visible */
  public void setVisible(boolean visible) {
    this.visible = visible;
  }

  public boolean getVisible() {
    return visible;
  }

  public void render(GL gl) {
    if (!visible)
      return;
    boolean lightingOn = true;
    // FIXME: this is too expensive; figure out another way
    //  if (glIsEnabled(GLEnum.GL_LIGHTING))
    //    lightingOn = true;

    if (lightingOn) {
      gl.glEnable(GL.GL_COLOR_MATERIAL);
      gl.glColorMaterial(GL.GL_FRONT_AND_BACK, GL.GL_AMBIENT_AND_DIFFUSE);
    }
    gl.glBegin(GL.GL_TRIANGLES);
    if (highlighted)
      gl.glColor3f(highlightColor.x(), highlightColor.y(), highlightColor.z());
    else
      gl.glColor3f(color.x(), color.y(), color.z());
    int i = 0;
    while (i < vertexIndices.length) {
      Vec3f n0 = curNormals[normalIndices[i]];
      Vec3f v0 = curVertices[vertexIndices[i]];
      gl.glNormal3f(n0.x(), n0.y(), n0.z());
      gl.glVertex3f(v0.x(), v0.y(), v0.z());
      i++;

      Vec3f n1 = curNormals[normalIndices[i]];
      Vec3f v1 = curVertices[vertexIndices[i]];
      gl.glNormal3f(n1.x(), n1.y(), n1.z());
      gl.glVertex3f(v1.x(), v1.y(), v1.z());
      i++;

      Vec3f n2 = curNormals[normalIndices[i]];
      Vec3f v2 = curVertices[vertexIndices[i]];
      gl.glNormal3f(n2.x(), n2.y(), n2.z());
      gl.glVertex3f(v2.x(), v2.y(), v2.z());
      i++;
    }
    gl.glEnd();
    if (lightingOn)
      gl.glDisable(GL.GL_COLOR_MATERIAL);
  }

  //----------------------------------------------------------------------
  // Used by subclasses to set up vertex, normals, and vertex and
  // normal indices.
  //

  protected void setVertices(Vec3f[] vertices) {
    this.vertices = vertices;
  }

  protected Vec3f[] getVertices() {
    return vertices;
  }

  protected void setNormals(Vec3f[] normals) {
    this.normals = normals;
  }

  protected Vec3f[] getNormals() {
    return normals;
  }

  protected void setVertexIndices(int[] vertexIndices) {
    this.vertexIndices = vertexIndices;
  }

  protected int[] getVertexIndices() {
    return vertexIndices;
  }

  protected void setNormalIndices(int[] normalIndices) {
    this.normalIndices = normalIndices;
  }

  protected int[] getNormalIndices() {
    return normalIndices;
  }

  //----------------------------------------------------------------------
  // Internals only below this point
  //

  private void consistencyCheck() {
    if (vertexIndices.length != normalIndices.length) {
      throw new RuntimeException("vertexIndices.length != normalIndices.length");
    }

    if ((vertexIndices.length % 3) != 0) {
      throw new RuntimeException("(vertexIndices % 3) != 0");
    }

    if ((curVertices != null) &&
        (vertices.length != curVertices.length)) {
      throw new RuntimeException("vertices.length != curVertices.length");
    }
  }

  private void recalcVertices() {
    if ((curVertices == null) ||
        (curVertices.length != vertices.length)) {
      curVertices = new Vec3f[vertices.length];
      for (int i = 0; i < vertices.length; i++) {
        curVertices[i] = new Vec3f();
      }
    }

    for (int i = 0; i < vertices.length; i++) {
      xform.xformPt(vertices[i], curVertices[i]);
    }

    if ((curNormals == null) ||
        (curNormals.length != normals.length)) {
      curNormals = new Vec3f[normals.length];
      for (int i = 0; i < normals.length; i++) {
        curNormals[i] = new Vec3f();
      }
    }

    for (int i = 0; i < normals.length; i++) {
      xform.xformDir(normals[i], curNormals[i]);
      curNormals[i].normalize();
    }
  }
}
